IEEE 979:2012 pdf free download

IEEE 979:2012 pdf free download.IEEE Guide for Substation Fire Protection.
smoke aspirating system: The principle of using an air sample drawn from the protected area into a high- humidity chamber combincd with a lowcring of chamber pressure to creatc an cnvimnmcnt in which ilic resultant moisture in the air condenses on any smoke particles present, forming a cloud. The cloud density is measured by a photoelectric principle. The density signal is processed and used to convey an alann condition when ii meets preset ‘iiteria
spot4 pe lunLtatlon detector: The principle of using a small amount of radioactive material to ionize the air between two differentially charged electrodes to sense the presence of smoke particles. Smoke particles entering the ionization volume decrease the conductance of the air by reducing ion mohility The reduced conductance signal is processed and used to convey an alarm condition when it meets preset criteria. This type of smoke detection is best applied to flaming or incipient fires in which small particulate matter is produced.
spot-type photoelectric detector: The principle of using a light soutce and a photosensitive sensor onto which the principal portion of the source emissions is focused. When smoke particles enter the light path. sonic of the light is scattered and some is absorbed, thereby reducing the light reaching the receising sensor. The light reduction signal is processed and used to convey an alarm condition when it meets preset criteria. This typc of smoke detection is best applied to tires in which larger particulate matter is penduced.
we-pilot line detector: A system of heat detection employing automatic sponklers on a pressurized wet pipe network. The activation of a sprinkler causes a loss in system pressure. which is annunciated as an alarm signal.
4. Fire hazards
4.1 General
The impact of fire hazards on health, safety. continuity of operations, and asset preservation is a reason to provide fire prevention, fire protection, and other fire safety measures. Fire hazards are the conditions that create the potential for a lire. Fire hazards have at least the following attnbutes:
— The magnitude of a possible fire
— The consequence of the potential loss
— The pro4ability of an occurrence over a period of time (ic., risk)
Subelauses 42 through 4.7 present recognized lire hazards found in substations.
Refer to k2 for additional information.
4.2 Combustible oil hazards
Based on mass and potential for energy release. mineral-oil-insulated equipment is normally the largest hid source present in most substations. Mineral-oil-insulated equipment includes the following.